March 19, 2021

expert reaction to Scotland study on living with children and COVID-19 risk in adults

A study published in the Archives of Disease in Childhood led by the University of Glasgow, in partnership with Public Health Scotland, looks at COVID-19 risk in adults sharing a household with young children.

Prof Keith Neal, Emeritus Professor of the Epidemiology of Infectious Diseases, University of Nottingham, said:

“This study has raised some very interesting questions about COVID-19 infections, children and possible cross immunity from other coronaviruses.

“By studying health care workers who were more exposed than average they demonstrated a reducing risk of infection with COVID-19 with each additional child aged 0-11 in the household.

“What is clear that having children aged 0-11 in schools at a time of significant community transmission was not associated with an increased risk of COVID-19 infection in adults living with children.

“Because health care workers are tested regularly the study was less likely to miss infections than those looking at other groups of people.

“If it is confirmed that one or more of the 4 coronaviruses that cause mild disease (colds) and readily spread between children do induce cross immunity in the adults they infect within households (and other places) this could have major implications on the policy of school closures.

“It is possible that the spread of the four mild illness-inducing other coronaviruses may have a benefit on COVID-19 over and above of any spread of COVID-19 within schools.

“Further work is needed in this area as it has major policy implications.”

Comment on both this study and the BMJ OpenSAFELY study:

Prof Mark Woolhouse, Professor of Infectious Disease Epidemiology, University of Edinburgh, said:

“Two papers published today shed light on the role of children in the transmission of COVID-19 and the risks to adults living in the same household.

“The paper by Forbes and colleagues¹ estimates the impact of living with children on the frequency and severity of COVID-19 infections in adults.

“This is an observational study based on the medical histories of twelve million adults.  The results from this type of study must be interpreted with care – there may be several possible explanations for any patterns found – but the work does add to a growing body of evidence about the role of children in the current pandemic.

“The findings of the study are complex and open to multiple interpretations.

“A key outcome is that adults over 65 living with children were at increased risk of dying from COVID-19 during the second, but not the first, wave.  As schools in England were open in the second, but not the first, wave, this result is consistent with a link between transmission in schools and severe COVID-19 in older co-residents.

“This study cannot establish whether any link is due to direct effects (school-acquired infections being brought into the household) or indirect effects (increased activity and exposure of adults in the household while children are in school).  However, the authors note that only 3% of adults over 65 share households with children, so any public health impact must be relatively small.

“Another key outcome is that adults 65 and under living with children were at decreased risk of dying from COVID-19 during both waves.  This is despite (in the second wave) their having slightly increased risks of being infected and hospitalised.  One possible explanation suggested by the authors is that adults living with children are generally healthier.

“A second paper by McAllister and colleagues² reports results from a similar study in Scotland.

“This study found that living with children under 12 protected adults against COVID-19 infection.  There was no increased risk to adults even when schools were open in Scotland.  The authors suggest that this may be due to the impact of adult immune systems of exposure to the mild coronavirus infections that circulate in young children.

“Together, these studies suggest two competing effects.  The presence of children in the household may increase the risk of exposure to COVID-19 – especially when schools are open – but for various reasons most adults in those households are less likely to develop severe disease, so the net public health impact is very low.

“The two studies published today add to a large body of evidence that has been accumulating since the earliest days of the pandemic suggesting that children play a limited role in COVID-19 transmission.  The evidence that closing schools causes short-term and long-term harms to children has always been much stronger than the evidence that closing schools has any substantial effect on the public health burden of COVID-19.”

1 BMJ OpenSAFELY paper: ‘Association between living with children and outcomes from covid-19: OpenSAFELY cohort study of 12 million adults in England’ by Harriet Forbes et al. will be published in the BMJ at 23:30 UK time on Thursday 18 March 2021, which is also when the embargo will lift.

DOI: 10.1136/bmj.n628

2 Archives of Disease in Childhood Scotland paper: ‘Living with Children and Adults’ Risk of COVID-19: Observational Study’ by Rachael Wood et al. will be published in the Archives of Disease in Childhood at 00:01 UK time on Friday 19 March 2021, which is also when the embargo will lift.

‘Living with Children and Adults’ Risk of COVID-19: Observational Study’ by Rachael Wood et al. was published in the Archives of Disease in Childhood at 00:01 UK time on Friday 19 March 2021.

Declared interests

Prof Mark Woolhouse: “No CoIs to declare.”

None others received.